Nanowires-assembled WO3 nanomesh for fast detection of ppb-level NO2 at low temperature

Abstract

Abstract Hierarchical WO 3 nanomesh, assembled from single-crystalline WO 3 nanowires, is prepared via a hydrothermal method using thiourea (Tu) as the morphology-controlling agent. Formation of the hierarchical architecture comprising of WO 3 nanowires takes place via Ostwald ripening mechanism with the growth orientation. The sensor based on WO 3 nanomesh has good electrical conductivity and is therefore suitable as NO 2 sensing material. The WO 3 nanomesh sensor exhibited high response, short response and recovery time, and excellent selectivity towards ppb-level NO 2 at low temperature of 160 ℃. The superior gas performance of the sensor was attributed to the high-purity hexagonal WO 3 with high specific surface area, which gives rise to enhanced surface adsorption sites for gas adsorption. The electron depletion theory was used for explaining the NO 2 -sensing mechanism by the gas adsorption/desorption and charge transfer happened on the surface of WO 3 nanomesh.